sizeof java object

Question

How can we find out the size of a java object??

Example:

class Person{
    String name;  
    int age;  

    public Person(String n, int a){  
          


        

Answer 1

Java has no built in sizeof operator.

You could try and use a serialization method, by serializing an object to memory and getting the size of that data, but that wouldn't necessarily be the size you want.

You could also have a method called sizeOf(), like this:

// returns the size of this object in bytes
int sizeOf()
{
     int size = 0;
     size += name.Length * 2; // each character in name is 2 bytes, no?
     size += 4; // for n, which is 32 bits = 4 bytes
}

Note that this implementation doesn't include the metadata inside name, only the number of bytes necessary to make the char[] for it.